VATICAN CITY, JAN. 23, 2011 (Zenit.org).- For the unity of Christians to be a reality, all Christians must make a serious commitment to conversion to Christ, says Benedict XVI.

The Pope reflected on the Week of Prayer for Christian Unity, under way through Tuesday, in the address he gave before praying the midday Angelus together with those gathered today in St. Peter"s Square.

"To be a sign and instrument in the world of intimate union with God and of unity among men," the Pontiff affirmed, "we Christians must base our life on these four cardinal principles: life founded on the faith of the Apostles transmitted in the living Tradition of the Church, fraternal communion, the Eucharist and prayer."

"Only in this way," he added, "being closely united to Christ, can the Church effectively accomplish her mission, despite the limits and failures of her members, despite the divisions."

"Every division in the Church is an offense to Christ," the Holy Father stated, noting that in Christ "we can find unity among ourselves, by the inexhaustible power of his grace."

"Serious commitment to conversion to Christ," he concluded, "is the way that will lead the Church, in the times disposed by God, to full visible unity."